Question 422162
against wind	1 1/6	hours					
with wind	 5/6	hours					
								
Distance = same=	21	miles					
plane speed	=x							
wind speed	=y							
t=d/r								
21/(x-y)=1.17	
1.17(x-y)=21.00	
1.17x-1.17y=21	....................1	
21/(x+y)= 5/6	
 5/6(x+y	)=21	
 5/6x+ 5/6y=21	...............2	
Multiply (1) by 	5							
Multiply (2) by	8							
we get								
5.83x-5.83y=105		
6.67x+6.67y=168		
12.5x=273					
/12.5							
x=21.84	mph	plane speed				
								
plug value of x in (1)								
1.17x-1.17y=21		
25.48-1.17y=21		
-1.17y=21-25.48				
-1.17y=-4.48					
y=3.84	mph wind speed